I am trying to connect different UAVs in ad-hoc manner.I am interested to use Wimax from the base station to the backbone UAV, that would be further connected with WIFI.
Of course it is possible to combine communication technologies (read here how it can be done with search and rescue drones: Chapter Tactical Communication for Cooperative SAR Robot Missions
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The use of WiMax is also investigated in that article, but not applied as it was a too expensive solution. Maybe your application scenario / business case is different.